Ignition system and control for burner and conveyor



Dec. 22, 1964 J. L. LA POINTE 3,162,429

IGNITION SYSTEM AND CONTROL FDR BURNER AND CONVEYOR Filed Sept. 28, 1961 RNERla FIG.

l. NY L INVENTOR. JOSEPH LEO LAPOINTE ATT'ORN EY BY A i,

United States Patent Ofiiice 3,162,429 Patented Dec. 22, 1964 3,162,429 IGNITION SYSTEM AND CONTROL FOR BURNER AND CONVEYOR Joseph Leo La Points, Detroit, Mich., assignor to Hupp Corporation, Cleveland, Ghio, a corporation of Virginia Filed Sept. 28, 1961, Ser. No. 141,379 11 Claims. (Cl. 263-6) This invention relates to an ignition system or control circuit for a burner or conveyor, and especially to a flame sensing element, an electrode element and control means responsive to relative displacement of one of said elements for automatically cutting 01f fuel to said burner and/or stopping a conveyor carrying work pieces heat processed by said burner.

An object of the present invention is to provide a control circuit for a burner means, having a flame sensing element means, an electrode element means, and means responsive to displacement of at least one of said element means out of a given position for cutting off the supply of fuel to said burner means.

A further object of the present invention is to provide a control circuit for a conveyor means sequentially moving work pieces past a heat processing burner means, comprising a flame sensing element means, an electrode element means, and means responsive to displacement of at least one of the element means out of a given position for de-energizing drive to said conveyor means.

A further object of the invention is to provide an ignition system for a burner using one or both of the control circuits mentioned in the two preceding paragraphs that will automatically ignite the burner, has electronic means responsive to the combustion of gas in the burner to turn off the gas igniter, rapidly senses and responds without delay to the presence or absence of a flame at the burner, will shut ofi flow of fuel to the burner if the burner fails to ignite, will automatically re-ignite the burner after the flame has blown out, and/ or has means responsive to failure of combustion of fuel in the burner to actuate relay means and shut off a solenoid operated valve to discontinue flow of fuel to the burner.

A further object of the invention is to provide a burner control, conveyor control, or ignition system characterized by its compact construction; minimum number of component parts; 10W manufacturing cost; fail safe operation; ease of use; long, trouble-free wear life; and safety features providing safe operating conditions.

These and other objects of the present invention will become more fully apparent by reference to the appended claims as the following detailed description proceeds in reference to the accompanying drawings wherein:

FIG. 1 is a schematic representation of a first form of a present invention; and

FIG. 2 is a schematic representation of a portion of a second form of the present invention.

This is an improvement on the invention disclosed in the co-pending application filed by John J. Fannon, Jr. and Joseph Leo La Pointe on September 28, 1961, Serial No. 141,479, and entitled Ignition System and Control For Fuel Burner.

FIG. 1 shows the first form of the invention. FIG. 2 shows a circuit component adapted to be substituted in FIG. 1, for the component shown therein at the correspondingly numbered terminals, to provide said second form of the invention with the remainder of FIG. 1. The first form of the invention in FIG. 1 will be described in complete detail first before later describing the second form of the invention in FIG. 2.

The control circuits, ignition systems, and control systemsfor a conveyor and burner in the present invention are especially adapted for heat processing conveyor moved work pieces in a safe manner, and are especially adapted for use on infrared radiant heater burners of the type shown in the G. Schwank United States patents, Nos. 2,775,294 and 2,870,830.

FIG. 1 discloses a conventional solenoid operated gas valve 14 for supplying and controlling the flow of combustible fluid fuel, such as gas, from supply line 18A to fluid fuel burner means 18. Air is aspirated into burner 18 by the gas and burned adjacent one surface of the burner to form flame 19. Burner housing 18 is made of metal or other electrically conductive material. Gas or fuel valve 14 is a conventional shut-off valve having valve 14A to open or close a port to control the flow of gas. Valve element 14A is urged to the valve closed position by a spring (not shown). Solenoid 13, upon energization, is effective to open valve element 14A in valve 14 against the action of the spring into the valve open position, while de-energization of solenoid 13 permits the spring to move valve element 14A to the valve closed position.

Time delay relaysVZ and V3 are of 'a conventional type in which heater elements 16 and 11 therein respectively are provided to heat to a pro-selected temperature in a pre-selected time so as to open or close associated respective contacts or switches 15 and 12 at the preselected time and temperature.

Conveyor 30 has endless conveyor belt 31 driven by motor 32 to conveyor work pieces or parts 33 in the direction of the arrow under flame 19 for heat processing of these parts 33.

Although any suitable circuit components may be used, it has been found in one suitable installation that a proper mode of operation is achieved by using components of the following sizes: transformer T1 has a 115 volt, cycle primary winding or coil Tl-P, 190 volt A.C. across secondary terminals T1-1 and T12 at no currents conditions, 6.3 volts 2 amps across secondary terminals Tl-Ii and T14, 24 volts across secondary terminals T1-4 and T1-5, ma. across terminals T1 1 and Til-5, 160 volts across terminals T1-5 and '11-6, and secondary coil T1-S having terminals T1-1, T12, T13, T1-4, T1S and T1-6; transformer T2 has a 5000 ohms primary coil and 333 ohms secondary coil, and has maximum impressed voltage across the primary coil of 2 volts and 400 microamps and across the secondary coil of 0.15 volt and 0.50 microamp; glow coil igniter transformer T3 has a volts, 2.5 amps primary coil and a 2.5 volts, 11 amps secondary coil; resistance Z1 is a 3 to 10 megohrns /2' Watt resistor; grid protector resistance Z2 is a 240 K ohms /2 watt resistor; resistance Z3 is a 2300 ohm potentiometer serving as a bias sensitivity control for tube V4; resistance Z4 is a one megohm /2 watt resistor; igniter coil H1 is a Nichrome heater element flow coil; thyratron tubes V1 and V4 are each a 2D21 thyratron, or any equivalent electronic valve with or without ground G2; and probe 20 is a metal probe constructed of lnconel or other suitable material.

The mode of operation should be readily apparent after considering the following description.

Closing main switch S1 energizes the primary and secondary coils of transformer T1 and igniter glow coil, positioned adjacent burner 18 for causing flame 19. Alternating current power is supplied through A.-C. power lines L1, L2 to primary coil T1-P and secondary coil Tl-S of transformer T1 after closing main switch S1 for supplying power to tubes V1 and V4. Closing switch S1 also energizes or supp-.ies alternating current power to igniter glow coil or igniter 10 by forming Circuit No. 1 through line L1, transformer T3, igniter glow coil 1%, normally closed contact R1-1 of relay R1. as a switch means in the igniter energizing circuit, and line L2.

.Sincetubes V1 and V4 disclosed herein require -approximately 10 to 15 seconds warmup time before they.

can operate, a suitable time delay is provided in the circuit by keeping open contact 12 of time delay relay tube V3 to prevent power being appliedtogas valve solenoid 13-until after waimup-has occurred. Closingma'm switch S1 energizes time relay relay tube V3-by forming- Circuit No.2 throughline L1, heater element ll of timedelay relay tube V3, and line L2. After the 10 to 15 seconds time delay haselapsed, heater element 11 of tube V3 closes its normally open contacts 12: (1) to energize solenoid 13 to open gascontrol valve 14 topermit gas to flow from' gas line 18Ainto burner 18 by forming Circuit No. 3 electrically connected in parallel with primary coil .T1-P of transformer T1 "through-line L1, normally open contact 12 now closed, normally closed'contact 15, normally closed. contact R2-1 of relay R2, valve solenoid '13, andlineLZ; and'(2) to? energize time delay relay tube V2 by forming Circuit No. 4 throughlineLl, normally open contact 12 now closed, heater element 16 of tube V2, normally closed contact R1-1 of relay RLand-line L2.

Now, energizedigniter 10 will ignite the gas mixture now permitted to flow from burner 18 through open valve -14 and willproduce flarne 19.

After the gasis ignited, flame 19 completes an electricalpathcausing thyratron tube Vl-to conduct, relay R1 to be energized, and igniter 10 and time delay relay heater element 16 to be de-energized. Tube V1 has cathode heater 22 energized by a circuit from transformer secondary winding terminals T1-3 and "fl-4. Flame 19 forms Circuit No. through series connected transformer tap T1-1, resistance Z1, junction Z4, burner housing 18, flame 19, flame sensing element means or probe 20 located adjacent burner 18 contiguous to or in flame 19 from burner 18, primary coil of transformer T2, and

transformer secondary tap Tl-6. Circuit No. 5 is energized by secondary coil Tl-S andelectrically connected to grid 25 at vjunction Z4. The voltage pulse or the potential at-junction Z4 produced by Circuit No. 5 is now sufficiently positive relative to cathode 23, because of the IR drop across resistance Z1, so that a glow discharget-akes place between-cathode '23 and starter anode or grid 25 sothe gas isionized in thyratron tube V1 and the tube conducts, during each half cycle that anode 24 is positive, so electronic -valve V1 isactuated to energize relay R1 by forming Circuit No. .6 energized by sec ondary coil Tl-S through transformer secondary terminal T1-5, cathode 23 of thyratron tube V1, anode 24 of tube V1, relay coil R1-C of relay 'RL-and transformer secondary terminal T1-6. Sensing element 20, electrically.connected togrid .25, thus senses the presenceof flame 19 by conduction of an electrical current along a path through flame 19 tocontrol the conduction actionof tube V1 .by grid 25. Rectifier or diode 26, located in series with thyratron V1, is inparallel with relay coil .R1-Cto prevent relay chatter because tube VLconductsonly dur: ing the positive half cycles, but any suitable unidirectional electronic valve, such as a condenser, may be so placed in parallel with relay coil R1-Cifor this same purpose.' Under normal conditions, Circuit No. 5 does not have sufficient current flowing through transformer T2, because of the resistance of flame 19;, to cause grid 40 of ,tube V4 to be sufliciently positive for causing tube V4 to conduct. Energizing relay coil Rl-C opens switch means or normally closed relay contact R1-1 now: (1) to break 'CircuitN-o. 1 to de-energ'ize and cutofi power to .ignite'r for conservation purposes when a flame 19 is present and thyratron V1 is energized, and (2) to break Circuit No. 4 to de-energize' heater element 16 of time delay ,relay tube V2. Gas valve 14 is open, igniter 10 isde-energized, heater element 16 of time delay tube V2 is de-energized, andfl'ame 19maintains this condition ,of operation.

Here, threeelectrode elements are provided in Circuit No. 5, including burner housing'elernent means 18, work piece element-means 33 through conveyor elementmeans 30, and probe element means 24]. If desired, a second probe, electrode or structural element means, similar to probe 20, can be located in flame 19 and directly electrically connected to junction Z4 and ground G1 with burner =18 and conveyor 30 eliminated from Circuit No. 5.

If flame 19 goes out,'tube V1 stops conducting, relay R1 is :de-energized 'igniter 10 is re-'energized, and heater element 16 oftime ,d'elayrelay tube V2 is re-energized.

If flame 1'9 goes out, lackof flame :19 causes sensing element 2% to control the action of tube V1 by breaking Circuit No; 5 so that the positivepotential at -jun'ction'Z4 -isreduced to reduce thepositive-bias on grid 2510f tube V1 to prevent tube V1 from-conducting. Since tube V1 rstops conducting, Circuit N0.--6 is broken to de energize relay tube V2 times-out, its-energized and heated heater element loopens its normally closed bimetal switcher .contact 15 'located'in valveenergizing Circuit No. 3 to break Circuit No. 3 tode-energize solenoid 13 and thus to close gas valve 14 .to cut-off the supply \of fuel to burner 18.

It should also readily be apparent that if, whenCircuit No.4 was first formed asfirst described heretofore, flame 19 was not produced within the predetermined periodof time established by-heater element 16'of time delay-relay tube V2," heater element 16opens (normally closed contact 15 to break Circuit No. 3 to 'de-energize solenoid coil 13 to close valve 14 in the same manner to shutoff the supply of .gas toburner 18.

Conveyor 30 has endless work piece conveyor belt 31 driven by a drive means, including motor 32, to 'convey work pieces orparts 33-in the direction of the arrow under flame 19 for heat "processing sequentially parts 33 moved by conveyor belt 3-1. Motor 32 is energized'in any suitable manner, such as by =forming Circuit No. 7 through line L1, ,motor 32, normallyclosed relay contact R3 1 of relay Rihand line L2.

When conveyed work piece parts 33, by becoming'dis- .placedon the :con-veyor'line, jam againstflarne probe 20' so as to risk damage to burner 18 mounted'on the oven wall and other components of the apparatus, a safety circuit protectsboth workpieces 33 and theconveyor by automatically stopping the heat processing of articles 33 by de-energizing conveyor motor 32 and closingfuel valve .14. When parts 33 are not sojammed and tube V1 is sensing the on condition of .flame 19-by;probe 20 being located ina given normal relative position relative to burner 18, conveyor 30 and work pieces 33, a voltage of 0.15 volt at 50 microamps may be "crossing flame 19 to grounded burner 18,-or to the aforementioned second probe or-electrode' element means, because of the high impedance of 3.8 megohmswith a frequency of 60 cycles at flame 19'. Then there is not suflici-ent current in Circuit No. 5,and;tnansformer T2 to -cause tube V4 to conduct. However, when piled up work pieces 33 on conveyor 30 cause flexible flameprobe, electrode or flame sensing element means 20 to bedisplaced out of its given normal position relative to burner 18, and to engage and to .groundagainst any of the otherelectrodes or structural element means, such as grounded metal burner housing element means 18, through work piece element .means 33 and grounded metal conveyor element means 30, or

change the electrical resistance in the path of Circuit No. 5 contiguous to flame probe 20. This may now cause a. 2 volts, 400 microamperes signal to flow through Circuit No. 5 and the primary of transformer T2. The potential difference between control grid 4% and cathode 41 of thyratro-n V4 is the summation of two potentials; (l) the potential from secondary terminal Tl-S to tap 43 caused by the IR drop across resistance Z3 energized by transformer secondary terminals 11-4 and Tl-S, and (2) the potential across the secondary coil of transformer T2. When the current in Circuit No. 5 is large, the potential across the secondary coil of transformer T2 is correspondingly large so that the potential diflerence between cathode 41, heated in the same manner as cathode 23, and control grid 40 of thynatron tube V4 is sufliciently positive on grid 49 to cause tube V4 to tire or conduct. Tap 43 is manually adjustable to provide sensitivity control so as to control firing of tube J4 at any desired degree of grounding of probe 20. When tube V4 fires, relay R2 is energized by form-ing Circuit No. 8 through transformer secondary terminal T1-5, cathode 4-1 of tube V4, anode 42 of tube V4, relay coil RZ-C of relay R2, and transformer secondary terminal "fl-6. Rectifier or diode 44, in parallel with relay coil RZ-C, prevents chattering of the relay coil in the same manner as earlier described for rectifier 26. Energizing relay R2 now: (1) opens normally closed relay contact R2-1 to break Circuit No. 3 to tie-energize solenoid 13 and close as valve 14, and (2) closes normally open relay contact R2-2 to sound warning buzzer 45 and to energize relay R3 to open relay contact R3-1 to break Circuit No. 7 to de-energize conveyor driving motor 32 to stop conveyor 38 by forming Circuit No. 9 through line L1, normally open contact 12 now closed, normally closed contact 15, normally open relay contact RZ-Z now closed, warning buzzer 45, conveyor stop relay coil R3C, and line L2. Now, conveyor 39 is stopped and no flame l9 exists so that the whole apparatus is shut down until the jamming and grounding of probe 20 is corrected.

The second form of the invention is shown in FIG. 2. It is exactly the same as the FIG. l form except that the circuitry in FIG. 2 between terminals 51, 52 and 53 (in cluding manually operated switch 55 and .neon glow lamp 56 or other suitable warning light) is substituted for tube V2 in FIG. 1 at terminals 51, 52 and 53. The sequence of operation and of circuit forming and breaking occurs the same as before described but with the following exceptions. First, Circuit No. 3 is now not formed until after switch 55 is manually closed so that the gas valve and ignition are manually operated, such as on a domestic oven or broiler igniter. Second, if any of these conditions: (1) flame 19 goes out after once lit, or (2) flame 19 is not originally produced have occurred so as to break sequentially Circuits Nos. and 6 to de-energize relay coil R1C, normally closed relay contact Rl-l will close to reform: (1) Circuit No. 4 so lamp 55 will now be energized, instead of heater element 16 of tube V2, to indicate lack of flame l9 and to indicate ignition on to the apparatus operator, and (2) Circuit No. 1 to re-energize igniter 19. After lamp 56 has been lit for a predetermined period of time, the operator may manually open switch 55 to break Circuit No. 3 to de-energize solenoid 13 to close gas valve 14 in the same manner as heating of element 16 in FIG. 1 automatically opened switch 15 in tube V2 to break Circuit No. 3 after the time delay.

It may now be readily appreciated that the control circuits and ignition systems in FIGS. 1 and 2 invention forms are effective as safeguards to assure that gas burner 18 is operating properly when gas valve 14 is open, to automatically ignite and reignite burner 18, and to automatically shut off the flow of fuel to burner 13 and to stop conveyor 3% when work pieces 33 jam up to cause grounding of flame probe 20. The apparatus is simple in construotion, requires a minimum number of operating parts, is compact, operates quickly without undue delay, is fail safe in that failure of substantially any of the component parts will operate to discontinue the flow of gas to burner 18 and require trouble shooting of the circuit to locate and repair the fault, prevents improper processing of work pieces 33 by shutting oil burner fuel and stopping conveyor 30 if jam up occurs, and has a substantially long, trouble free wear life.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive with the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by US. Letters Patent is:

l. A control system for a fluid fuel burner means, comprising a structural element means providing part of the structure of said system and burner means and a flame sensing element means located in a given relative position contiguous to the location of a flame from said burner means, means responsive to flame sensing by said flame sensing element means for providing ignition at said burner means when the flame is absent, and means responsive to displacement of at least one of said element means out of said given relative position to a fuel cut-off position into contact with the other element means for cutting off the supply of fuel to said burner means.

2. In combination, a work piece conveyor means; drive means for moving such conveyor means; a burner means for heat processing sequentially work pieces moved by said conveyor means; and a control system for said conveyor means, comprising a structural element means providing part of said combination and a flame sensing element means located in a given relative position contiguous to the location of a flame from said burner means, means responsive to flame sensing by said flame sensing element means for providing ignition at said burner means when the flame is absent, and means responsive to the displacement of at least one of said element means out of said given relative position to a conveyor drive de-energizing position for de-energizing the drive means to said conveyor means.

3. An apparatus for heat processing of articles by a burner means, comprising a structural element means in said apparatus and a flame sensing element means located in a given relative position contiguous to the location of a flame from said burner means to sense the presence of the flame by an electrical path through said flame between said element means, means responsive to flame sensing by said flame sensing element means for providing ignition at said burner means when the flame is absent, and means responsive to displacement of at least one of said element means out of said given relative position and toward the other element means to reduce the electrical resistance in said path contiguous to said flame'sensing element means for automatically stopping the heat processing of articles.

4. An apparatus for heat processing articles by a burner means controlled by an ignition system, comprising a work piece conveyor means; drive means for moving said conveyor means; a burner means for heat processing sequentially work pieces moved by said conveyor means; and a control and burner ignition system for said conveyor means and burner means, comprising an igniter adjacent said burner means, a structural element means providing part of said apparatus and a flame sensing element means located in a given relative position contiguous to the location of a flame from said burner means to sense the presence of the flame by an electrical path through said flame, means responsive to flame senisng by said flame sensing element for energizing said igniter when the flame is absent, means responsive to flame sensing by said S..An apparatus, as set forth in tclaim 4, with said I -structural element means being said burner means.

6. An apparatus, 'as set forth in claim 4, with each of said element meansbeing a'fiame probe adapted to bel'o catedin-said flame.

7. An apparatus, as set forthin claim 4, with said structural element means being said conveyor meansand i adapted t0.be any Work pieces thereon.

' 8. An apparatus, asset forth in claim 4, with fuel shutoif -means' including fuel switch means vfor ontrolling a fuel valve and-beingadaptedto'be opened to-shut off said fuel afterrav predetermined period-oftime in the event that the :burnertdoes not" ignite.

--9. .An -appar'atus, 'as set 'forthinsclaim '8, with thermal fiimed'el-ay'switchmeans including a'heater ielement energized when the fiame is absent and ineluding said fuel witch means being normally closed and adapted to be 8 automatically opened 'by energizing 'said heater element forsaid predetermined'peniodof time. 7

10. An apparatus, as set forth in claim 8,'with a'warning light energized when the flame is'absent, andsaid fuel 'switchmeans being manually operable after said warning light has been lit for said predetermined period of time.

11. An apparatus, as 'set forth in claim 4, with said structure element means being said burner means and adapted to be saidconveyed work pieces straddling said flame sensing element, so'that any displacement of said flame sensing element by a Work piece against either of said structural-elements will shut 011? the fuel supply and stopsaid conveyor means.

References'Cited 'by the Examiner UNITED STATES PATENTS Van Norstrand' 2638 X 1,936,784 1'1/33' Diamond 158l24 X 2,025,542 12/35 Lugar 263-6 X 2,162,501 6/39 Draper 15828 2,388,124 10/45 Crews 15828 2,619,595 11/52 Russell 15828 CHARLES SUKALO, Primary Examiner. FREDERICK LTVIATTESON, IR, Examiner.

UNITED srATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3, 162,429 December 22 1964 Joseph Leo La Pointe It is hereby certified that error appears in the above numbered patent reqairing correction and that the said Letters Patent should read as corrected below.

Column 2, line 28, for "conveyor" read convey line 53, for "flow" read glow column 3, line 7, for "time relay relay" read time delay relay line 11, for "contacts" read contact column 6, line 73, for "senisng" read sensing Signed and sealed this 29th day of June 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attcsting Officer Commissioner of Patents 

1. A CONTROL SYSTEM FOR A FLUID FUEL BURNER MEANS, COMPRISING A STRUCTURAL ELEMENT MEANS PROVIDING PART OF THE STRUCTURE OF SAID SYSTEM AND BURNER MEANS AND A FLAME SENSING ELEMENT MEANS LOCATED IN A GIVEN RELATIVE POSITION CONTIGUOUS TO THE LOCATION OF A FLAME FROM SAID BURNER MEANS, MEANS RESPONSIVE TO FLAME SENSING BY SAID FLAME SENSING ELEMENT MEANS FOR PROVIDING IGNITION AT SAID BURNER MEANS WHEN THE FLAME IS ABSENT, AND MEANS RESPONSIVE TO DISPLACEMENT OF AT LEAST ONE OF SAID ELEMENT MEANS OUT OF SAID GIVEN RELATIVE POSITION TO A FUEL CUT-OFF POSITION INTO CONTACT WITH THE OTHER ELEMENT MEANS FOR CUTTING OFF THE SUPPLY OF FUEL TO SAID BURNER MEANS. 